Rotary kiln provided with seal mechanism

ABSTRACT

A so-called rotary kiln in which a material is continuously heated by means of a rotatably supported cylinder is provided with a seal mechanism for blocking the outer air from the interior of the cylinder, hereinafter referred to as the &#39;&#39;&#39;&#39;rotary kiln proper&#39;&#39;&#39;&#39;. The seal mechanism for the rotary kiln undergoes various adverse conditions involved inherently in the operation of the rotary kiln, such as vibration in the peripheral portion of the rotary kiln proper during rotation, thermal deformation, thermal elongation and contraction of the rotary kiln proper, continuous operation at high temperatures and the like. In the rotary kiln of this invention, improved air-tightness can be maintained stably even under such conditions, principally being achieved by the provision of an elastic member supporting the weight of a hood independently of the rotary kiln proper for preventing a deflected load from being imposed on the seal mechanism, and preferably, a specific seal mechanism especially fit for such an elastic member is employed.

United States Patent 1 lnoue et al.

[ 1 Dec.2,1975

[ ROTARY KILN PROVIDED WITH SEAL MECHANISM [73] Assignee: Kobe SteelLtd., Kobe, Japan [22] Filed: May 28, 1974 21 Appl. No.: 473,575

Szymanski 34/242 Hobbs 432/115 mar Primary ExaminerJohn J. CambyAttorney, Agent, or FirmOblon, Fisher, Spivak, McClelland & Maier [57]ABSTRACT A socalled rotary kiln in which a material is continuouslyheated by means of a rotatably supported cylinder is provided with aseal mechanism for blocking the outer air from the interior of thecylinder, hereinafter referred to as the rotary kiln proper". The sealmechanism for the rotary kiln undergoes various adverse conditionsinvolved inherently in the operation of the rotary kiln, such asvibration in the peripheral portion of the rotary kiln proper duringrotation, thermal deformation, thermal elongation and contraction of therotary kiln proper, continuous operation at high temperatures and thelike. In the rotary kiln of this invention, improved air-tightness canbe maintained stably even under such conditions, principally beingachieved by the provision of an elastic member supporting the weight ofa hood independently of the rotary kiln proper for preventing adeflected load from being imposed on the seal mechanism, and preferably,a specific seal mechanism especially fit for such an elastic member isemployed.

4 Claims, 3 Drawing Figures US. Patent Dec. 2, 1975 ROTARY KILN PROVIDEDWITH SEAL MECHANISM BACKGROUND OF THE INVENTION Field of the InventionThe present invention relates generally to rotary kilns in which amaterial is continuously heated by means of a rotatably supportedcylinder, and more particularly to an improved rotary kiln having a sealmechanism for providing a greater degree of air tightness of thecylinder than former kilns possessed.

Rotary kilns of the type characterized herein are broadly employed aseffective heating kilns for the burning of cement and the calcination oflime and the like. In such rotary kilns, it is generally unnecessary toattain complete interception of the air currents from the'interior ofthe kiln unless special articles or materials are being heat-treatedtherein. However, when such rotary kilns are used for the preparation ofreduced pellets and in the thermal decomposition treatment of wastes,such as plastic and rubber wastes, it is necessary to completely blockthe outer air from the interior of the kiln proper by means of a sealmechanism in order to prevent the oxidation of such reduced pellets, the

leakage of resulting gases or oils and the occurrence of an explosionwhich might be caused by the incorporation of air.

Various improvements have been. made on the seal mechanism in connectionwith rotary kilns in which airtightness should be attained. In the casewhere such scaling is effected between the rotary kiln proper and afixing member, because of poor rotation precision of the peripheralportion of the rotary kiln or thermal deformation and thermal elongationor contraction of the rotary kiln per se, a deflected load isdiscontinuously imposed on the slidingface of the seal mechanism. Further, since a non-metallic material constituting this sliding face issubjected to high temperatures during the operation, even if improvedseal mechanisms are employed, they are readily destroyed in a short spanof time. Accordingly, no rotary kiln that can be operated stably andcontinuously for a long period of time is now available. Especially,there are no rotary kilns now available having a great diameter rotarykiln proper in which a good seal can be attained stably when theoperation is continued for a long period of time.

SUMMARY OF THE INVENTION It is therefore a primary object of the presentinvention to provide a rotary kiln which can overcome the formerproblems characterized herein which are encountered in the conventionalrotary kilns and in which an improved seal can be attained stably for along duration.

Another object of the present invention is to provide a rotary kiln inwhich there is no deflected load discontinuously imposed on the sealmechanism of the kiln.

Still another object of the present invention is to provide a rotarykiln in which a mechanical seal per se is so disposed that no deflectedload is imposed thereon, especially on a packing thereof composed of anonmetallic material.

A further object of the present invention is to provide a rotary kiln inwhich thermal deformation and thermal elongation and contraction of therotary kiln proper do not adversely affect the seal mechanism of thedevice.

The foregoing and other objects are achieved according to the presentinvention through the provision of a rotary kiln which is characterizedby a rotary kiln proper, a hood covering the end portion of the rotarykiln proper, a seal mechanism providing a seal between the rotary kilnand the hood, and an elastic member supporting the weight of the hoodseparately from the weight of the rotary kiln proper.

In the rotary kiln of the invention being constructed according to thespecific teachings thereof, even if the precision of the rotation of therotary kiln proper is poor at its peripheral portion, the hood followsthe rotary kiln proper during such rotation and it is kept in the stateof floating on the rotarykiln proper regardless of the vertical load, sothat a deflected load is prevented from being imposed on the sealmechanism.

Ina preferred embodiment of the invention, a metal ring is provided inthe seal mechanism and the elastic member is disposed so that it canmove in the direction parallel with the axial direction of the rotarykiln proper. In this embodiment the intended seal can be at-' tainedmore effectively. More specifically, the metal ring improves the abilityof the hood to follow after the rotary kiln and protects thenon-metallic material of the seal mechanism. Further, the movement ofthe elas- Various other objects features and attendant advantages of thepresentinvention will be more fully appreciated as the same becomesbetter understood from the" 1 following detailed description whenconsidered in connection with'the accompanying drawings, in which likereference numerals designate like or corresponding parts in the severalviews, and wherein:

FIG. 1 is a partial side view illustrating one embodiment of a rotarykiln constructed according to the present invention; 2

FIG. 2 is a partial side view illustrating another embodiment of arotary kiln also constructed according to the teachings of the presentinvention; and

FIG. 3 is a partial sectional view illustrating an example of a sealmechanism to be used in the rotary kiln of the present invention andcontructed according to the teachings thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotary kiln of thepresent invention may be either the internal heating type or theexternal heating type. In the accompanying drawing, the invention isillustrated by reference to embodiments concerning an external heatingtype rotary kiln to be used as an apparatus for thermally decomposingplastic or rubber wastes and for recovering oil or gaseous fuel, oruseful materials such as carbides and the like.

Referring now to the drawings, and more particularly to FIGS. 1 and 2, arotary kiln proper l is shown being rotatably supported by a roller 21and a hood 8 is disposed to cover an end portion of the rotary kilnproper. As is illustrated in FIG. 3, a seal mechanism for providing aseal between the rotary kiln proper 1 and the hood 8 is formed from adouble-cylinder sleeve 2 fitted integrally by soldering or the like tothe end portion of the rotary kiln proper l, aplurality of ring-likepackings 3, shown as being four in number, mounted on the periphery ofthe outer cylinder wall, and a plurality of corresponding metal rings 4,shown as being five in number, being alternately arranged with thepacking 3 onthe double-cylinder sleeve 2. These ring-like packings 3 andthe metal rings 4 are secured within a ring member 5 fitted to the hood8 by means of a clamping member 6 and a securing bolt 7 for adjustingthe force of the binding packings 3. A projection 9 and a control metalfitting 10 are mounted between the hood 8 and the sleeve 2,respectively, so that the hood 8, the ring member 5, the metal rings 4and the packings 3 can move along with any axial movement of the rotarykiln proper l which may be caused by the thermal expansion thereof. Agrease nipple 12 is mounted on the ring member 5 and a lubricant, suchas a heat-resistant grease, is fed therethrough on the sliding surfacebetween the packings 3 and the metal rings 4 and the sleeve 2.

In the embodiment shown in FIG. 1, the hood.8 is shown being supportedindependently from the rotary kiln proper 1 through an elastic orresilient member composed of a plurality of springs 22, a plurality ofposition-adjusting members 23 disposed in series with the elastic memberand a moving truck 24 carrying the springs 22 and the position-adjustingmembers 23.

In the embodiment shown in FIG. 2, the hood 8 is supported through aspring 25, apposition-adjusting member 26 and a chain 27, and the hood 8is likewise supported independently from the rotary kiln proper 1.

In both embodiments, it can be seen readily from the drawings that theposition-adjusting members may take the form of threaded boltsprojecting through a plate and having nuts threadably secured on oneside of the plate for varying the projection of the bolts through theplate, whereby the vertical disposition of the hood may be adjustedreadily.

In the rotary kiln of this invention having such structure as describedherein, even when the rotary kiln proper 1 is shaken through itsrotation and the sliding face of the seal mechanism is displaced by suchshaking of the rotary kiln proper 1, the hood 8 follows the rotary kilnproper 1 without causing any deflected load on the sliding surface, anda good seal can thereby be attained stably for a long period of time. Inorder to further improve the followability of the hood 8 after therotary kiln proper 1, the metal rings 4 can be provided in the sealmechanism. By provision of these metal rings 4, it is possible toprevent the deflected wearing of the packings 3. More specifically, ifeither the position-adjusting member 23 or 26 is so regulated that theweight of the seal mechanism and the hood 8, including the ring member5, is well balanced with the supporting force of the respective elasticmember 22 or 25 when the hood 8 is at a proper position, then during therotation of the rotary kiln proper l, the hood 8 can easily follow therotary kiln proper l with a very small force and the force forsupporting the structural members, such as the rotary kiln proper l, thehood 8 and the like, is not transmitted through the sliding surface tothe seal mechanism. Further, if the above-mentioned metal rings 4 areemployed, even the small force indicated herein is not imposed on thepackings 3 in a deflected manner, and the sliding face or surface of theseal mechanism can be maintained in good condition.

Moreover, since the hood 8 is so disposed that it can move in thedirection parallel to the axis of the rotary kiln proper 1', it is notat all influenced by thermal elongation or contraction of the rotarykiln proper l. Namely, a good seal can therefore be attained stablywithout changing the relative positions of the sleeve 2 and the sealmechanism.

Obviously many modifications and variations of the present invention arepossible in light of these teachings. It is therefore to be understoodthat within the scope of the appended claims, the invention may bepracticed otherwise than as specifically described herein.

What is claimed as new and intended to be covered by Letters Patent is:

l. A rotary kiln provided with a seal mechanism, comprising:

a rotary kiln proper;

a hood covering one end portion of said rotary kiln proper;

a seal mechanism providing a seal between said rotary kilnproper andsaid hood which has metal rings, packings, and means for lubricating thesliding faces of said metal rings and packings;

an elastic means for supporting the weight of the hood independently ofsaid rotary kiln proper; and

a position-adjusting means connected to said elastic means forvertically adjusting the hood supported thereby.

2. The rotary kiln set forth in claim 1 which further comprises:

a moving truck supporting said elastic means for moving said elasticmeans in a direction parallel to the axial direction of said rotary kilnproper.

3. The rotary kiln set forth in claim 1, wherein said hood is suspendedthrough said elastic means and said position-adjusting means.

4. The rotary kiln set forth in claim 1, wherein said metal rings andpacking are arranged alternately.

1. A rotary kiln provided with a seal mechanism, comprising: a rotarykiln proper; a hood covering one end portion of said rotary kiln proper;a seal mechanism providing a seal between said rotary kiln proper andsaid hood which has metal rings, packings, and means for lubricating thesliding faces of said metal rings and packings; an elastic means forsupporting the weight of the hood independently of said rotary kilnproper; and a position-adjusting means connected to said elastic meansfor vertically adjusting the hood supported thereby.
 2. The rotary kilnset forth in claim 1 which further comprises: a moving truck supportingsaid elastic means for moving said elastic means in a direction parallelto the axial direction of said rotary kiln proper.
 3. The rotary kilnset forth in claim 1, wherein said hood is suspended through saidelastic means and said position-adjusting means.
 4. The rotary kiln setforth in claim 1, wherein said metal rings and packing are arrangedalternately.